A hard lump on hemorrhoids can be caused by thrombosis, local inflammation, venous rupture and other factors. 1. thrombus mechanization: hemorrhoids at the tortuous expansion of the venous hemorrhoidal nucleus and with thrombosed external hemorrhoids, thrombus mechanization may occur, resulting in hemorrhoids local hard pimple-like manifestations. 2. local inflammation: hemorrhoids without timely and effective treatment, the condition of recurrent episodes, delayed, can lead to the rectum anus local recurrent infections, can appear inflammatory polyps, can be manifested as hemorrhoids on the long a hard pimple. 3. venous rupture: hemorrhoids are mainly composed of varicose veins, when the veins rupture, blood extravasation can be in the hemorrhoids local formation of blood clots, can be manifested as a hard lump. The hard pimples on the hemorrhoids, should be timely medical identification and diagnosis, under the guidance of a professional doctor to actively carry out reasonable and standardized treatment, will help to early relief of discomfort symptoms, reduce the symptoms of the disease.